This invention relates to apparatus for lifting and lowering items, and more particularly for automatic lifting and lowering of visual display apparatus such as television sets, video monitors, and the like.
Television sets have become larger over the years. Recently, the television displays, or monitors, have become very large, often separated from the television set. Some are thin but of large area including the new plasma displays. They have become so large that it is often desirable to hide them when not in use. U.S. Pat. No. 4,151,804 issued Jan. 1, 1979 to Wache discloses a device that elevates and lowers a horizontal television support with an electric motor so that the screen may be lowered into a cabinet out of sight when not in use. It employs a threaded bushing riding on a rotating screw for power raising and lowering, and a scissors arrangement to maintain the horizontal position.
Applicant has been marketing a television lift that uses a platform sup ported at opposite sides by a pair of lift assemblies that raise and lower in synchrony. With the new flat plasma displays, it would be desirable to provide a more compact device with simple construction to take advantage of the compact configuration of these new displays. It would be useful to have the lift mechanism behind the display, where it is concealed, instead of on both sides of the display, which requires a wider cabinet.
It is accordingly an object of the invention to provide a lift that would be simpler, more compact, and that could be located beneath the large displays for concealment. It is another object that the device be able to extend the elevation of its horizontal support platform above its minimum overall height.
A first embodiment of the invention comprises a solitary lift assembly that lies behind or in front of the display. A motor drives a pair of threaded vertical rods mounted on a base in synchrony. A threaded nut on each rod is affixed to a bushing sliding on a smooth vertical rod adjacent each threaded rod. A platform is affixed to both bushings and extends away from the rods to support the display or television set thereon and raise and lower it as desired, while the mechanism is behind or in front of the display.
A second embodiment of the invention comprises a solitary lift assembly on a base that may lie beneath the display. A motor drives a pair of threaded vertical rods in synchrony. A threaded nut on each rod is affixed to a bushing sliding on a first smooth vertical rod adjacent each threaded rod. A vertical bar adjacent each threaded rod is affixed to each bushing. A sprocket atop each bar rotates about a horizontal axle affixed to each bar. A second smooth vertical rod adjacent each bar is provided with a sliding support bushing. A platform is affixed to both support bushings and extends forward of the rods to support the display or television set thereon and raise and lower it as desired. A chain for each sprocket has one end connected to the base, the other end coupled to the support bushing with the chain engaging the sprocket therebetween. As the sprockets are lifted by the action of the threaded rods, the platform rises. It is pulled up by a chain at each end, until it is above the top of the threaded rods.
These and other objects, features, and advantages of the invention will become more apparent when the detailed description is studied in conjunction with the drawings in which like elements are designated by like reference characters in the various drawing figures.